OpenRaiser/Intern-Atlas huggingface dataset:
FHHOP: A Factored Hybrid Heuristic Online Planning Algorithm for Large POMDPs
Venue: arXiv cs.AI 2012
Year: 2012

Planning in partially observable Markov decision processes (POMDPs) remains a challenging topic in the artificial intelligence community, in spite of recent impressive progress in approximation techniques. Previous research has indicated that online planning approaches are promising in handling large-scale POMDP domains efficiently as they make decisions "on demand" instead of proactively for the entire state space. We present a Factored Hybrid Heuristic Online Planning (FHHOP) algorithm for large POMDPs. FHHOP gets its power by combining a novel hybrid heuristic search strategy with a recently developed factored state representation. On several benchmark problems, FHHOP substantially outperformed state-of-the-art online heuristic search approaches in terms of both scalability and quality.
Latent Dirichlet Allocation Uncovers Spectral Characteristics of Drought Stressed Plants
Venue: arXiv cs.LG 2012
Year: 2012

Understanding the adaptation process of plants to drought stress is essential in improving management practices, breeding strategies as well as engineering viable crops for a sustainable agriculture in the coming decades. Hyper-spectral imaging provides a particularly promising approach to gain such understanding since it allows to discover non-destructively spectral characteristics of plants governed primarily by scattering and absorption characteristics of the leaf internal structure and biochemical constituents. Several drought stress indices have been derived using hyper-spectral imaging. However, they are typically based on few hyper-spectral images only, rely on interpretations of experts, and consider few wavelengths only. In this study, we present the first data-driven approach to discovering spectral drought stress indices, treating it as an unsupervised labeling problem at massive scale. To make use of short range dependencies of spectral wavelengths, we develop an online variational Bayes algorithm for latent Dirichlet allocation with convolved Dirichlet regularizer. This approach scales to massive datasets and, hence, provides a more objective complement to plant physiological practices. The spectral topics found conform to plant physiological knowledge and can be computed in a fraction of the time compared to existing LDA approaches.
Factorized Multi-Modal Topic Model
Venue: arXiv cs.LG 2012
Year: 2012

Multi-modal data collections, such as corpora of paired images and text snippets, require analysis methods beyond single-view component and topic models. For continuous observations the current dominant approach is based on extensions of canonical correlation analysis, factorizing the variation into components shared by the different modalities and those private to each of them. For count data, multiple variants of topic models attempting to tie the modalities together have been presented. All of these, however, lack the ability to learn components private to one modality, and consequently will try to force dependencies even between minimally correlating modalities. In this work we combine the two approaches by presenting a novel HDP-based topic model that automatically learns both shared and private topics. The model is shown to be especially useful for querying the contents of one domain given samples of the other.
Several AES Variants under VHDL language In FPGA
Venue: arXiv cs.CR 2012
Year: 2012

This paper provides four different architectures for encrypting and decrypting 128 bit information via the AES. The encryption algorithm includes the Key Expansion module which generates Key for all iterations on the fly, Double AEStwo-key triple AES, AESX and AES-EXE. These architectures are implemented and studied in Altera Cyclone III and STRATIX Family devices.
LSBN: A Large-Scale Bayesian Structure Learning Framework for Model Averaging
Venue: arXiv cs.LG 2012
Year: 2012

The motivation for this paper is to apply Bayesian structure learning using Model Averaging in large-scale networks. Currently, Bayesian model averaging algorithm is applicable to networks with only tens of variables, restrained by its super-exponential complexity. We present a novel framework, called LSBN(Large-Scale Bayesian Network), making it possible to handle networks with infinite size by following the principle of divide-and-conquer. The method of LSBN comprises three steps. In general, LSBN first performs the partition by using a second-order partition strategy, which achieves more robust results. LSBN conducts sampling and structure learning within each overlapping community after the community is isolated from other variables by Markov Blanket. Finally LSBN employs an efficient algorithm, to merge structures of overlapping communities into a whole. In comparison with other four state-of-art large-scale network structure learning algorithms such as ARACNE, PC, Greedy Search and MMHC, LSBN shows comparable results in five common benchmark datasets, evaluated by precision, recall and f-score. What's more, LSBN makes it possible to learn large-scale Bayesian structure by Model Averaging which used to be intractable. In summary, LSBN provides an scalable and parallel framework for the reconstruction of network structures. Besides, the complete information of overlapping communities serves as the byproduct, which could be used to mine meaningful clusters in biological networks, such as protein-protein-interaction network or gene regulatory network, as well as in social network.
Influence of the Dynamic Social Network Timeframe Type and Size on the Group Evolution Discovery
Venue: arXiv cs.SI 2012
Year: 2012

New technologies allow to store vast amount of data about users interaction. From those data the social network can be created. Additionally, because usually also time and dates of this activities are stored, the dynamic of such network can be analysed by splitting it into many timeframes representing the state of the network during specific period of time. One of the most interesting issue is group evolution over time. To track group evolution the GED method can be used. However, choice of the timeframe type and length might have great influence on the method results. Therefore, in this paper, the influence of timeframe type as well as timeframe length on the GED method results is extensively analysed.
Use of Repositories and its Significance for Engineering Education / El Uso de Repositorios y su Importancia para la Educación en Ingeniería
Venue: arXiv cs.DL 2012
Year: 2012

Institutional repositories are deposits of different types of digital files for access, disseminate and preserve them. This paper aims to explain the importance of repositories in the academic field of engineering as a way to democratize knowledge by teachers, researchers and students to contribute to social and human development. These repositories, usually framed in the Open Access Initiative, allow to ensure access free and open (unrestricted legal and economic) to different sectors of society and, thus, can make use of the services they offer. Finally, that repositories are evolving in the academic and scientific, and different disciplines of engineering should be prepared to provide a range of services through these systems to society of today and tomorrow.
Attribute-Based Encryption for Circuits from Multilinear Maps
Venue: arXiv cs.CR 2012
Year: 2012

In this work, we provide the first construction of Attribute-Based Encryption (ABE) for general circuits. Our construction is based on the existence of multilinear maps. We prove selective security of our scheme in the standard model under the natural multilinear generalization of the BDDH assumption. Our scheme achieves both Key-Policy and Ciphertext-Policy variants of ABE.
SMCHR: Satisfiability Modulo Constraint Handling Rules
Venue: arXiv cs.PL 2012
Year: 2012

Constraint Handling Rules (CHRs) are a high-level rule-based programming language for specification and implementation of constraint solvers. CHR manipulates a global store representing a flat conjunction of constraints. By default, CHR does not support goals with a more complex propositional structure including disjunction, negation, etc., or CHR relies on the host system to provide such features. In this paper we introduce Satisfiability Modulo Constraint Handling Rules (SMCHR): a tight integration of CHR with a modern Boolean Satisfiability (SAT) solver for quantifier-free formulae with an arbitrary propositional structure. SMCHR is essentially a Satisfiability Modulo Theories (SMT) solver where the theory T is implemented in CHR. The execution algorithm of SMCHR is based on lazy clause generation, where a new clause for the SAT solver is generated whenever a rule is applied. We shall also explore the practical aspects of building an SMCHR system, including extending a "built-in" constraint solver supporting equality with unification and justifications.
The origin of Mayan languages from Formosan language group of Austronesian
Venue: arXiv cs.CL 2012
Year: 2012

Basic body-part names (BBPNs) were defined as body-part names in Swadesh basic 200 words. Non-Mayan cognates of Mayan (MY) BBPNs were extensively searched for, by comparing with non-MY vocabulary, including ca.1300 basic words of 82 AN languages listed by Tryon (1985), etc. Thus found cognates (CGs) in non-MY are listed in Table 1, as classified by language groups to which most similar cognates (MSCs) of MY BBPNs belong. CGs of MY are classified to 23 mutually unrelated CG-items, of which 17.5 CG-items have their MSCs in Austronesian (AN), giving its closest similarity score (CSS), CSS(AN) = 17.5, which consists of 10.33 MSCs in Formosan, 1.83 MSCs in Western Malayo-Polynesian (W.MP), 0.33 in Central MP, 0.0 in SHWNG, and 5.0 in Oceanic [i.e., CSS(FORM)= 10.33, CSS(W.MP) = 1.88, ..., CSS(OC)= 5.0]. These CSSs for language (sub)groups are also listed in the underline portion of every section of (Section1 - Section 6) in Table 1. Chi-squar test (degree of freedom = 1) using [Eq 1] and [Eqs.2] revealed that MSCs of MY BBPNs are distributed in Formosan in significantly higher frequency (P < 0.001) than in other subgroups of AN, as well as than in non-AN languages. MY is thus concluded to have been derived from Formosan of AN. Eskimo shows some BBPN similarities to FORM and MY.
Secure Abstraction with Code Capabilities
Venue: arXiv cs.CR 2012
Year: 2012

We propose embedding executable code fragments in cryptographically protected capabilities to enable flexible discretionary access control in cloud-like computing infrastructures. We are developing this as part of a sports analytics application that runs on a federation of public and enterprise clouds. The capability mechanism is implemented completely in user space. Using a novel combination of X.509 certificates and Javscript code, the capabilities support restricted delegation, confinement, revocation, and rights amplification for secure abstraction.
Quality of Service Support on High Level Petri-Net Based Model for Dynamic Configuration of Web Service Composition
Venue: arXiv cs.SE 2012
Year: 2012

Web services are widely used thanks to their features of universal interoperability between software assets, platform independent and loose-coupled. Web services composition is one of the most challenging topics in service computing area. In this paper, an approach based on High Level Petri-Net model as dynamic configuration schema of web services composition is proposed to achieve self adaptation to run-time environment and self management of composite web services. For composite service based applications, in addition to functional requirements, quality of service properties should be considered. This paper presents and proves some quality of service formulas in context of web service composition. Based on this model and the quality of service properties, a suitable configuration with optimal quality of service can be selected in dynamic way to reach the goal of automatic service composition. The correctness of the approach is proved by a simulation results and corresponding analysis.
A Stochastic Geometry Approach to Energy Efficiency in Relay-Assisted Cellular Networks
Venue: arXiv cs.NI 2012
Year: 2012

Though cooperative relaying is believed to be a promising technology to improve the energy efficiency of cellular networks, the relays' static power consumption might worsen the energy efficiency therefore can not be neglected. In this paper, we focus on whether and how the energy efficiency of cellular networks can be improved via relays. Based on the spatial Poisson point process, an analytical model is proposed to evaluate the energy efficiency of relay-assisted cellular networks. With the aid of the technical tools of stochastic geometry, we derive the distributions of signal-to-interference-plus-noise ratios (SINRs) and mean achievable rates of both non-cooperative users and cooperative users. The energy efficiency measured by "bps/Hz/W" is expressed subsequently. These established expressions are amenable to numerical evaluation and corroborated by simulation results.
Weighted Modal Transition Systems
Venue: arXiv cs.LO 2012
Year: 2012

Specification theories as a tool in model-driven development processes of component-based software systems have recently attracted a considerable attention. Current specification theories are however qualitative in nature, and therefore fragile in the sense that the inevitable approximation of systems by models, combined with the fundamental unpredictability of hardware platforms, makes it difficult to transfer conclusions about the behavior, based on models, to the actual system. Hence this approach is arguably unsuited for modern software systems. We propose here the first specification theory which allows to capture quantitative aspects during the refinement and implementation process, thus leveraging the problems of the qualitative setting. Our proposed quantitative specification framework uses weighted modal transition systems as a formal model of specifications. These are labeled transition systems with the additional feature that they can model optional behavior which may or may not be implemented by the system. Satisfaction and refinement is lifted from the well-known qualitative to our quantitative setting, by introducing a notion of distances between weighted modal transition systems. We show that quantitative versions of parallel composition as well as quotient (the dual to parallel composition) inherit the properties from the Boolean setting.
Survival Network Design of Doubling Dimension Metrics
Venue: arXiv cs.DS 2012
Year: 2012

We investigate the Minimum Weight 2-Edge-Connected Spanning Subgraph (2-ECSS) problem in an arbitrary metric space of doubling dimension and show a polynomial time randomized $(1+ε)$-approximation algorithm.
Sparse Stochastic Processes and Discretization of Linear Inverse Problems
Venue: arXiv cs.IT 2012
Year: 2012

We present a novel statistically-based discretization paradigm and derive a class of maximum a posteriori (MAP) estimators for solving ill-conditioned linear inverse problems. We are guided by the theory of sparse stochastic processes, which specifies continuous-domain signals as solutions of linear stochastic differential equations. Accordingly, we show that the class of admissible priors for the discretized version of the signal is confined to the family of infinitely divisible distributions. Our estimators not only cover the well-studied methods of Tikhonov and $\ell_1$-type regularizations as particular cases, but also open the door to a broader class of sparsity-promoting regularization schemes that are typically nonconvex. We provide an algorithm that handles the corresponding nonconvex problems and illustrate the use of our formalism by applying it to deconvolution, MRI, and X-ray tomographic reconstruction problems. Finally, we compare the performance of estimators associated with models of increasing sparsity.
Steganalysis of Transcoding Steganography
Venue: arXiv cs.CR 2012
Year: 2012

TranSteg (Trancoding Steganography) is a fairly new IP telephony steganographic method that functions by compressing overt (voice) data to make space for the steganogram by means of transcoding. It offers high steganographic bandwidth, retains good voice quality and is generally harder to detect than other existing VoIP steganographic methods. In TranSteg, after the steganogram reaches the receiver, the hidden information is extracted and the speech data is practically restored to what was originally sent. This is a huge advantage compared with other existing VoIP steganographic methods, where the hidden data can be extracted and removed but the original data cannot be restored because it was previously erased due to a hidden data insertion process. In this paper we address the issue of steganalysis of TranSteg. Various TranSteg scenarios and possibilities of warden(s) localization are analyzed with regards to the TranSteg detection. A steganalysis method based on MFCC (Mel-Frequency Cepstral Coefficients) parameters and GMMs (Gaussian Mixture Models) was developed and tested for various overt/covert codec pairs in a single warden scenario with double transcoding. The proposed method allowed for efficient detection of some codec pairs (e.g., G.711/G.729), whilst some others remained more resistant to detection (e.g., iLBC/AMR).
Some Chances and Challenges in Applying Language Technologies to Historical Studies in Chinese
Venue: arXiv cs.CL 2012
Year: 2012

We report applications of language technology to analyzing historical documents in the Database for the Study of Modern Chinese Thoughts and Literature (DSMCTL). We studied two historical issues with the reported techniques: the conceptualization of "huaren" (Chinese people) and the attempt to institute constitutional monarchy in the late Qing dynasty. We also discuss research challenges for supporting sophisticated issues using our experience with DSMCTL, the Database of Government Officials of the Republic of China, and the Dream of the Red Chamber. Advanced techniques and tools for lexical, syntactic, semantic, and pragmatic processing of language information, along with more thorough data collection, are needed to strengthen the collaboration between historians and computer scientists.
Bipolar Proof Nets for MALL
Venue: arXiv cs.LO 2012
Year: 2012

In this work we present a computation paradigm based on a concurrent and incremental construction of proof nets (de-sequentialized or graphical proofs) of the pure multiplicative and additive fragment of Linear Logic, a resources conscious refinement of Classical Logic. Moreover, we set a correspon- dence between this paradigm and those more pragmatic ones inspired to transactional or distributed systems. In particular we show that the construction of additive proof nets can be interpreted as a model for super-ACID (or co-operative) transactions over distributed transactional systems (typi- cally, multi-databases).
Model Validation in Ontology Based Transformations
Venue: arXiv cs.LO 2012
Year: 2012

Model Driven Engineering (MDE) is an emerging approach of software engineering. MDE emphasizes the construction of models from which the implementation should be derived by applying model transformations. The Ontology Definition Meta-model (ODM) has been proposed as a profile for UML models of the Web Ontology Language (OWL). In this context, transformations of UML models can be mapped into ODM/OWL transformations. On the other hand, model validation is a crucial task in model transformation. Meta-modeling permits to give a syntactic structure to source and target models. However, semantic requirements have to be imposed on source and target models. A given transformation will be sound when source and target models fulfill the syntactic and semantic requirements. In this paper, we present an approach for model validation in ODM based transformations. Adopting a logic programming based transformational approach we will show how it is possible to transform and validate models. Properties to be validated range from structural and semantic requirements of models (pre and post conditions) to properties of the transformation (invariants). The approach has been applied to a well-known example of model transformation: the Entity-Relationship (ER) to Relational Model (RM) transformation.
A one-bit swap object using test-and-sets and a max register
Venue: arXiv cs.DC 2012
Year: 2012

We describe a linearizable, wait-free implementation of a one-bit swap object from a single max register and an unbounded array of test-and-set bits. Each swap operation takes at most three steps. Using standard randomized constructions, the max register and test-and-set bits can be replaced by read-write registers, at the price of raising the cost of a swap operation to an expected O(max(log n, min(log t, n))) steps, where t is the number of times the swap object has previously changed its value and n is the number of processes.
A structural analysis of the A5/1 state transition graph
Venue: arXiv cs.DC 2012
Year: 2012

We describe efficient algorithms to analyze the cycle structure of the graph induced by the state transition function of the A5/1 stream cipher used in GSM mobile phones and report on the results of the implementation. The analysis is performed in five steps utilizing HPC clusters, GPGPU and external memory computation. A great reduction of this huge state transition graph of 2^64 nodes is achieved by focusing on special nodes in the first step and removing leaf nodes that can be detected with limited effort in the second step. This step does not break the overall structure of the graph and keeps at least one node on every cycle. In the third step the nodes of the reduced graph are connected by weighted edges. Since the number of nodes is still huge an efficient bitslice approach is presented that is implemented with NVIDIA's CUDA framework and executed on several GPUs concurrently. An external memory algorithm based on the STXXL library and its parallel pipelining feature further reduces the graph in the fourth step. The result is a graph containing only cycles that can be further analyzed in internal memory to count the number and size of the cycles. This full analysis which previously would take months can now be completed within a few days and allows to present structural results for the full graph for the first time. The structure of the A5/1 graph deviates notably from the theoretical results for random mappings.
Graph Subsumption in Abstract State Space Exploration
Venue: arXiv cs.LO 2012
Year: 2012

In this paper we present the extension of an existing method for abstract graph-based state space exploration, called neighbourhood abstraction, with a reduction technique based on subsumption. Basically, one abstract state subsumes another when it covers more concrete states; in such a case, the subsumed state need not be included in the state space, thus giving a reduction. We explain the theory and especially also report on a number of experiments, which show that subsumption indeed drastically reduces both the state space and the resources (time and memory) needed to compute it.
On the Transfer of Information and Energy in Multi-User Systems
Venue: arXiv cs.IT 2012
Year: 2012

The problem of joint transfer of information and energy for wireless links has been recently investigated in light of emerging applications such as RFID and body area networks. Specifically, recent work has shown that the additional requirements of providing sufficient energy to the receiver significantly affects the design of the optimal communication strategy. In contrast to most previous works, this letter focuses on baseline multi-user systems, namely multiple access and multi-hop channels, and demonstrates that energy transfer constraints call for additional coordination among distributed nodes of a wireless network. The analysis is carried out using information theoretic tools, and specific examples are worked out to illustrate the main conclusions.